如何使用Boost连接C ++中的字符串向量？

Question

I have a vector of strings, like this:

{"abc"}{"def"}{"ghi"}

I want to concatenate them into a single string, with a separator like "-".

Is there a concise (pretty) way of doing this without using a typical for loop? I have c++03 and boost available to me.

Answer 1

Sure, boost provides a convenient algorithm for achieving what you are trying to do. In higher level languages you may have spotted a join function. Boost provides an equivalent algorithm in the join function.

#include <boost/algorithm/string/join.hpp>
using namespace std;

string data[] = {"abc","def","ghi"};
const size_t data_size = sizeof(data) / sizeof(data[0]);
vector<string> stringVector(data, data + data_size);
string joinedString = boost::algorithm::join(stringVector, "-");

Answer 2

Just for reference, there is currently a proposal for std::join , which you can check out here .

But since you have boost available, you can use boost::algorithm::join , which takes a sequence of strings and a separator, like so:

#include <iostream>
#include <string>
#include <vector>

#include <boost/algorithm/string/join.hpp>

int main() {
  std::vector<std::string> words;
  words.push_back("abc");
  words.push_back("def");
  words.push_back("ghi");
  std::string result = boost::algorithm::join(words, "-");
  std::cout << result << std::endl;
}

Prints:

abc-def-ghi

Answer 3

Another option using only the STL is:

std::ostringstream result;
if (my_vector.size()) {
    std::copy(my_vector.begin(), my_vector.end()-1,
              std::ostream_iterator<string>(result, "-"));

    result << my_vector.back();
}

return result.str()